[Freeswitch-users] KVM vs. XEN virtualization

[Giovanni Maruzzelli]

+1

sent from my mobile,
Giovanni Maruzzelli
cell: +39 347 266 56 18
On Apr 9, 2015 9:01 PM, "William King" <william.king at quentustech.com> wrote:

> I'm surprised nobody has suggested doing point to point(FS to FS) within
> the same data center testing to remove the provider from the mix, then
> doing a packet capture on the receiving box. Wireshark will be able to
> determine the network jitter. Once you can determine and compensate for
> the level of RTP network jitter, then you can start looking for
> potential audio issues.
>
> I've seen situations like you are describing, and they've all come down
> to the host machine was overloaded either at the CPU level, or the
> network stack.
>
> William King
> Senior Engineer
> Quentus Technologies, INC
> 1037 NE 65th St Suite 273
> Seattle, WA 98115
> Main:   (877) 211-9337
> Office: (206) 388-4772
> Cell:   (253) 686-5518
> william.king at quentustech.com
>
> On 04/03/2015 05:16 PM, Stanislav Sinyagin wrote:
> > hi,
> >
> > Here are some test results which might be interesting:
> >
> > I've set up a test FreeSWITCH server at digitalocean (they use KVM),
> > and originated test calls to some ITSP accounts. Each call played a
> > test sound file (voice samples from ITU:
> > http://www.itu.int/net/itu-t/sigdb/genaudio/AudioForm-g.aspx?val=1000050
> > ), and on the receiving end another FreeSWITCH server was recording
> > the received session. The receiving server was on a XEN VM. Both
> > servers talked G711 to their corresponding ITSP accounts.
> >
> > Then I compared the source audio and received audio in Audacity editor.
> >
> > The tests showed that the received voice wave shifts 20ms from the
> > original sound every few seconds, randomly back and forward. This
> > skewing was always present, regardless of ITSP and time of day.
> >
> > Then I moved the sending server to a XEN VM, and the waves appeared
> > almost perfectly synchronized (there was a 5ms skew in one test, and I
> > guess it's related to transcoding buffer, as the sound was obviously
> > transcoded).
> >
> > The effect was always visible with a 30-second sample, and I also made
> > additional tests with 2-minute samples.
> >
> > It would also be interesting to test this from a VmWare VM. If someone
> > wants to run such a test, feel free to contact me directly.
> >
> >
> > cheers,
> > stan
> >
> > _________________________________________________________________________
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> >
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>
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